Spark-plug.



W; E. SHERBONDY.

SPARK PLUG. APPLICATION FILED Auc.l9. 1915.

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'lflllllllllllm $1, Qttooniq Patnted Apr. 24,1917.

UNITED STATES PATENT OFFICE. i

WILLIAM E, SHEBBONDY, OF CLEVELAND. OHIO.

SPARK-PLUG.

To all "IF/00771. it may concern.

lie it known that l. \lnmrvu l). Sin-tie noxln', a citizen of the lnitcd States. resid iue at tleveland. in the county of tuvahoga and State of Ohio. have invented certain new and useful lln n'oveinents in Spark- Plugs. of which the Following is a specification.

This invention relates to spark plugs. the

moisture or otherwise is prevented. and in which also the conduit wire is not connected directly with the top of the central electrode. wherein certain advantages are ohtained.

in the drawings aeeompaurine and forming'a part oi this specification Figure 'l is a side vi'ew of this improved spark plug: Fig. 2 is a vertical sectional view thereof: Fig. 3

.is norms-sectional \lOW taken in line 3-4) of Fig. 2: and Fig. l is a top view of the plug. Similar characters of reference indicate correspoiuline parts in the different figures of the drawings Spark plugs as ord'inarily constructed comprisea metal shell threaded to he turned into the head of a. gas engine and. this hell .carries an o lterterminal wire and an inner terminal wire insulated from the shell usually by porcelain. This porcelain projects ahove the top of the. shell For the,com eotion of the conduitwire to the central electrode at tlietop oi the porcelain, and this projectin; portion of the porcelain is' Frequently ln'oken' or. cracked; elther accidentally or through. carelessness when placing the plug in the: engine ori-emoving it for cleaning purposes.requiring the plug to he entirely :poreelain'.

ticc to make this projecting portion of the porcelain of (p1it;o so|ne length. which, of course. increasesthe liability of hreakagr'e.

disassembled an'dthe substitution of a new Moreover it has heen the prac Frequentlrhy reason of moisture or oil on :thefiutside of the. porcelain oi coi'e short eircu iting hetween the shell and the upper" projecting portion of. the. central electrode takes. place. It i. also well understood that a'small deposit of carbon on the inside walls of the shell and around the porcelain core Specification of Letters Patent.

Application filed August 19, 1916.

Patented Apr. 24, 1917.

Serial No. 115.761.

not inl'reuuentlv Forms a circuit to the central electrode thus causing! a short circuit, so that the plug: hecomes foul and useless.

The present i1n n-ovement overcomes these several diszulvantagreshecause it permits the use of a very short porcelain core ahove the bushing and also protects that short core not only from hreakagje and cracking but. from moisture.

in thepreferred form thereof herein shown and descrihed this improved spark plu comprises a hexagonal shell 2 centrally hored tor the reception of the insulator 0r porcelain carrying the central electrode 4. This shell has the llsllzll chamher or petticoat 3 formed at flu-lower end thereof aroundthe central electrode and carries at such lower end the outer terminal or wire. 6 and is also provided with the proper threads to' enable-the shell to he turned into the head of the engine. The upper end of the shell is provided with a chamber 7 interiorly threaded as at and into this chamber the r upper end of the porcelain projects. the '80,

porcelain heine' held within the shell by a suitahle hushing 5 turned into the threaded hore ot" the shellat the lower end of the chamlwr. 'lhis chainher-is of sufficient size to permit thehushing to he turned into posi- .tion or removed 'as occasion should require.

(arried h the upper end of the shell and closing the chamber is a threaded closureor plut 10 ot suitahle insulating material. This closure carries a terminal rod or twin ll located to form a spark gap 12 hetweer its lower end and the top of the .celjitral' electrode. The upper projectingportion of this rod is tl1re: uled-for the rem-ptiol-rof the; usual nuts 13 h mean-s of whirl|.,th

duit wire is connected with the closufie or plug. The shell adjacent to the spark gap 12 is provided with suitahle. openings which may he closed by mica'or other transparent i'uat'erial located around the inner wall of the chamher and through Avhich thespark .need project only a short distanceheyond itshushing, just suflicientto insulatvthe' upper end of the entral electrode carried by the core or porcelain from the bushing. By the present improvement it will also be observed that the conduit wire is connected with the plug or closure of the shell and not directly with the central clectnale as is usual heretofore. so that the tightening of the nuts on the rod 11 does not in any way tend to move or shiftthe central electr de.

f is the usual practice of a mechanic hefore placing the plug in the engine to make sure that the spark gap at the lower end ot the plug is the proper one. this being in many instances about a thirtv-sechnd of an inch. and frequently it is ne essaejy to bend one of the spark gap wires toward or from each other. whichever happens to be the asicst: for the mechanic. so that it is not infrequent to bendthc central electrode wire toward the outer shell wire. In conseiplence when the conduit wire is connected to the upper end of the central electrode or wire the turning ot' the nuts has a tendency to cause the central wire to rotate in the core or por elain'so that if the central wire has been bent. toward the. outer or shell wire before the plug has been placed in the engine the rotating ot' the central wire by turning the clan'ipi'ng nuts when the. conduit wire is connected to the upper end of this central wire causes the central wire sometimes to rotate. toward or from the central wire so as to increase or decrease the spark gap between the terminal wires and put the plug out of commission. The user,ho\vever, does not know this until he attempts to run his engine and even then it requires some time to find out what is. wrong, not expecting trouble from the spark plug, especially if he has just placed a. new one in the engine. By the present improvement, however, there is no possibility of turning thementral wire, since the conduit wire is not connected therewith, but is connected with the rod inthe closure or plug which has no direct connection with the central electrode carried by the porcelain.

By forming a spark gap at the upper end ofthe porcela greater resistance is also oll'ercd'to the t out so that it is intensified and this causes the spark to jump the gaps with greater etliciency.

In addition to the foregoing the formation of the protecting chamber around the upper end of the core or 'iorcelain enables the shell to be made with a long hex which very n'iaterially facilitates the use of a wrench in removing and replacing the plug in position in the engine.

The insulated plug hereinbefore referred to is provided with a knurled edge 14 whereby it may be readily turned into and out of the shell and by loosening the clamping nut; connectingthe conduit, wire with this plug the plug itself may be removed without the shell having a relatively Y necessity of removing the terminal wire from the plug if desired. 1

The various details may he more or less changed without departing from the spirit or scope of this innn'oveim'nt.

T claim as my invention:

1. A spark plug comprising a one-piece longhcx shell having an exteriorly threaded lower end and an interiorly threaded chamber at. its upper end. an insulating core carried by said shell and projecting into and terminating within said chamber and carrying a central electrode. an insulating plug threaded into said chamber and carrying means for connecting a conduit wire with said electrode.

spark plug comprising a one-piece long hex shell having an cxteriorly threaded lower end and an interiorly threaded chamher at its upper end. an insulating core car ried by said shell and projecting into and terminating within said chamber and carry ing a central electrode, an insulating plug threaded into said chamber and carrying means for connecting a conduit wire with said electrode. said means spaced from the central electrode to form a spark gap, said shell having adjacent. to said spark gap one or more openings therein.

3. A spark plug comprising a one-piece long hex shell having an cxteriorly threaded lower end and an interiorly threaded chamber atits upper end, an insulating core carried by said shell and projecting into and terminating within said chamber and carrying a central electrode, an insulating plug threaded into said tfilltlll'llml and carrying means for connecting a conduit wire, with said elee-' trode, said means spaced from the central electrode to form a spark gap, said-shell having adjacent to said more openings therein, and transparent material located in said chamber and covering said opening or openings.

4. A spark plug comprising an integral long hex on its exterior. and an exteriorly threaded chamber at itslower end and an interiorlythrcaded chamher at its upper end, said chambers having a communicating bore having an annular shoulder, an insulating core having a shoulder in juxtaposition to the shoulder of the. bore and having its ends projecting into and terminating within said chambers, the bore adjacent to the upper chamber being interiorly threaded, a bushing Within said upper chamber and fitting said bore threads for holding the insulating core in position and an insulating plug closing the upper chamber and carrying a rod for conducting the current to the central electrode.

5.. A spark plug comprising an integralshell having a relatively long hex on its exterior and an exterio-rly threaded chamber at its lower end and an interiorly threaded spark gap one or chamber at its upper end of greater diameter than said lower chamber, said chambers having a communicating bore having an annular shoulder, an insulating .corehaving a shoulder in juxtaposition to the shoulder of the bore and having its ends projecting into and terminating within said chambers, the bore adjacent to the upper chamber being intcriorly threaded, a bushing within salcl upper chamber and fitting said bore threads for holding the insulating core in position, an insulating plug closing the upper cham her and carrying a rod for conducting the current to the central electrode.

6. A spark plug comprising a one-piece shell having a centrally located bore therein terminating at its upper end in an enlarged chamber, an insulating core within said shell and having an electrode and having its upper end projecting into and tern'iinating within said chamber, and means for closing said chamber and carrying means for connecting the conduit wire with said electrode.

'7. A spark plug comprising only the fol lowing members: a one-piece shell having a long hex on the exterior thereof and an exterior thread at its lower end and provided with a pair of chambers, one at its upper end and the other at its lower and With-ill terior threads between said chambers, said upper chamber having one 01' more sight openings therein, an insulated core having a central electrode with the upper end of the core projecting into the upper chamber, a bushing engaging the interior threads of the shell for securing the core in place, a terminal carried at the lower end of the shell to form a spark gap, a one-piece insulating closure for'the upper end of the shell and having a central rod spaced from the central electrode aof the core, means for securing the terminal jwire to the plug, and means located in the upper chamber for closing the sight opening.

8. A spark plug comprising a one-piece shell having a centrally located bore therein terminating at its upper end in an enlarged chamber, an insulating core Within said shell and having an electrode and having its upper end projecting into and terminating within said chamber, means for closing said chamber and carrying means for connecting a conduit wire with said electrode, said shell having above said bore and around the en-,

larged chamber an angular formed exterior portion for the reception of a wrench.

Signed at Cleveland, in the county of Cuyahoga, this 28th day of July, 1916.

WILLIAM E. SHERBONDY. 

